Marble cakes are homey and festive at the same time. A marble cake looks slick when you slice into it and reveal the delicate pattern of the two batters swirled together.
My first experience working with this type of mixture came about as the result of a marbled chocolate terrine that appeared first in the pages of the old Cook's Magazine, and then in my chocolate book. Everything about it was right—the texture, the flavor, the quantity of the mixture in relation to the mold—everything, that is, except the marbling. Even when I hardly mixed the white and dark chocolate mixtures at all, what I got was a few streaks of dark and white, and mostly a muddy combined color.
After several frustrating attempts I realized that I had too much dark chocolate and re-cast the recipe so that there was twice as much white chocolate, and the terrine mixture marbled perfectly. This marble cake is proportioned in the same way: rather than dividing the base batter in half, I like to remove about a third of it and add the chocolate. Thanks to my old friend Ceri Hadda who shared her mother's recipe years ago.